LONDON -- The Hawk-Eye line-calling system used at Wimbledon may not be quite as accurate as people think.

Two British scientists have done a study that raises the fallibility of the technology that has been the final arbiter of whether balls are in or out on Wimbledon's courts since 2007.

"It's absolutely vital to have a health warning stamped on this because what you see with Hawk-Eye doesn't always correspond to what's actually happened," said Harry Collins, a social sciences professor at Cardiff University.

"It's very misleading to think that we can have a technological fix for human disagreements in tennis," he said.

Collins and colleague Robert Evans authored a paper on public perceptions of Hawk-Eye to be published in July in the journal Public Understanding of Science.

At Wimbledon, Hawk-Eye has 10 cameras positioned around the courts. The technology reconstructs the ball's most likely path by combining its trajectory using images from the cameras. Hawk-Eye does not reproduce what actually happened, but what was statistically most likely to have happened.

That subtlety, Collins said, is often lost on tennis players, officials and spectators.

"When [Hawk Eye] says that a ball was 1 millimeter in, what they should say is that 'it was 1 millimeter in, we think,'" he said.

The technology has divided players. While Roger Federer dismissed Hawk-Eye as "nonsense" after its introduction at the Australian Open last year, Andy Roddick is an avowed fan.

Former Wimbledon champion Lindsay Davenport said she has confidence in Hawk-Eye and believes it is accurate.

"It gives you peace of mind as a player," she said this week. "I think it takes a lot of pressure off the umpires to try and make too crazy of a call and interject."

During last year's Wimbledon final, a series of Hawk-Eye challenges from Rafael Nadal infuriated Federer. The Swiss thought he had won the third set when a line call challenge from Nadal reversed the decision.

On Hawk-Eye's Web site, an analysis of the disputed call states that it was "likely" that the ball was in by 1 millimeter (0.04 inches). Federer ultimately won the championship, but not before complaining to the chair umpire that the electronic system was "killing" him.

Paul Hawkins, managing director of Hawk-Eye technology, says the line-calling system has gone through more than 1,000 tests. "We've gotten every single one of the tests correct," he said.

"Everyone in tennis is very happy with the system," he added.

Hawkins said that Hawk-Eye's margin of error averaged about 3.6 millimeters (0.14 inches) and that the system was around 99.9 percent accurate.

"Hawk-Eye isn't infallible, but it's pretty damned close," he said.

Aside from Wimbledon, Hawk-Eye is also used at the U.S. Open and the Australian Open. The system is also used for line calls in cricket.

FIFA authorities considered using Hawk-Eye to rule on disputed goals in soccer, but decided in March to put off introducing the technology.

The International Tennis Federation tested Hawk-Eye's accuracy in nearly 800 separate trials before introducing the system at major tournaments.

According to the ITF criteria, any electronic line-calling system must be able to judge a ball in or out within 5 millimeters (0.20 inches). Incorrect calls are allowed, so long as they are not more than 10 millimeters (0.40 inches) off.

"On no occasion have we said that this technology is perfect," said Stuart Miller, head of science and technical issues at the ITF.

Miller said that accompanying Hawk-Eye's rulings with a disclaimer that the system's reconstructions were only a best guess of what happened would only confuse the public.

"All you would be doing would be to create something for people to argue about," Miller said. "That would make the whole system more complex and lead to more disputes than it resolves."

Collins and Evans said that while what Hawk-Eye achieves is remarkable, its use in tennis needs to be refined.

"It should be used like a spell-checker on your computer," Collins said. "It's not right all the time, but it's a useful adviser."

Beforehand

06-19-2008, 08:09 PM

Roger's going to beat someone to death this year!

scoobs

06-19-2008, 08:10 PM

Well this isn't news at all - nobody has ever pretended that Hawkeye was 100% accurate and that it shows exactly what happens. It has margin for error and it shows what it thinks was the most likely thing to have happened based on the data it has obtained.

The margin for error is known about and considered to be acceptable - and the margin for error is considered to be less than that for human linecalling by eye.

So what else is new?

I mean, a human linecall isn't 100% accurate - it's based on what one pair of eyes and one brain interprets from what is seen in a split second, adjudicated by an umpire.

Beforehand

06-19-2008, 08:13 PM

Well this isn't news at all - nobody has ever pretended that Hawkeye was 100% accurate and that it shows exactly what happens. It has margin for error and it shows what it thinks was the most likely thing to have happened based on the data it has obtained.

The margin for error is known about and considered to be acceptable - and the margin for error is considered to be less than that for human linecalling by eye.

So what else is new?

I mean, a human linecall isn't 100% accurate - it's based on what one pair of eyes and one brain interprets from what is seen in a split second, adjudicated by an umpire.

:eek: Chris, you knew about this all along, and didn't tell any of us? ;)

Johnny Groove

06-19-2008, 08:13 PM

Nadal was the first to figure this out, in Dubai 07 vs. Youzhny

scoobs

06-19-2008, 08:14 PM

:eek: Chris, you knew about this all along, and didn't tell any of us? ;)
I'm sure I sent out a memo...somewhere...

Oh Bugger.

;)

BIGMARAT

06-19-2008, 08:18 PM

Nadal was the first to figure this out, in Dubai 07 vs. Youzhny

It's a trivia!

MIMIC

06-19-2008, 08:36 PM

I saw a Hawk Eye error once (can't remember that match). The instant replay showed that the ball clearly hit the line but Hawk Eye ruled it out.

Fedex

06-19-2008, 08:41 PM

This is not news. We knew it was not 100% accurate.

habibko

06-19-2008, 08:43 PM

still much better than shitty line calls at break points, I suggest they introduce Hawk Eye for foot faults too

Bernard Black

06-19-2008, 08:48 PM

So the average error is 3.6mm? That seems a lot to me, I'd be curious to know what the maximum error is then?

Whilst I think Hawkeye is a much better system than relying on human judgement, I hope they work to improve the technology somewhat, surely they can get it to be more accurate than that.

scarecrows

06-19-2008, 08:49 PM

Nadal was the first to figure this out, in Dubai 07 vs. Youzhny

he also invented the "whine for 5 minutes about the Hawk Eye" which was later adopted from Federer and taken to new dimensions

jazar

06-19-2008, 08:50 PM

quite a lot of people have known this for quite a while

Wicked0987

06-19-2008, 09:02 PM

Proffesor in social sciences?

Since when is tracking and coordinates an aplication of social sciences?

Or Levy

06-19-2008, 09:13 PM

I admit, I like hawkeye.

I mean, I think it is better for it to be wrong on a (Sorry, Rogi) a one-milimter out call, but to avoid having those 5 cm out calls getting called in.